elegant tern
{{short description|Species of bird}}
{{Speciesbox
| image = 2022-04-16 Thalasseus elegans, Upper Newport Bay, California 4.jpg
| image_caption = Displaying birds at Upper Newport Bay, California
| status = NT
| status_system = IUCN3.1
| genus = Thalasseus
| species = elegans
| authority = (Gambel, 1849)
| synonyms = Sterna elegans Gambel, 1849
| range_map = Thalasseus elegans map.svg
}}
The elegant tern (Thalasseus elegans) is a tern in the family Laridae. It breeds on the Pacific coast of southern California in the United States and western Mexico, and migrates south to Peru, Ecuador and Chile for the northern winter; in the late summer and fall, some also disperse north to Oregon and more rarely Washington.
This species breeds in very dense colonies on coasts and islands, including Isla Rasa{{Cite web|url=http://www.sdnhm.org/oceanoasis/fieldguide/islarasa.html|title = SDNHM - Isla Rasa}} and Montague Island in Mexico,{{cite web|url=http://elibrary.unm.edu/sora/wb/v24n04/p0259-p0262.pdf|title=Searchable Ornithological Research Archive|access-date=22 February 2009|archive-date=16 June 2012|archive-url=https://web.archive.org/web/20120616125354/http://elibrary.unm.edu/sora/wb/v24n04/p0259-p0262.pdf|url-status=dead}} as well as South Bay Salt Works (San Diego) and Bolsa Chica Ecological Reserve in California.{{cite web | title=Elegant Terns expanding in California | website=Audubon California | date=2015-07-09 | url=https://ca.audubon.org/news/elegant-terns-expanding-california | access-date=2025-02-08}} Exceptionally, vagrants can occur inland on suitable large freshwater lakes.{{cite web | title=Observations | website=iNaturalist | date=2008-03-19 | url=https://www.inaturalist.org/observations?subview=map&taxon_id=144542 | access-date=2025-02-08}}
The elegant tern feeds by plunge-diving for fish, almost invariably from the sea, like most Thalasseus terns. It usually dives directly, and not from the "stepped-hover" favored by the Arctic tern. The offering of fish by the male to the female is part of the courtship display.
This Pacific species has wandered to western Europe as a rare vagrant on a number of occasions. The first European record was at Carlingford Lough in County Down, Northern Ireland, in late June 1982.{{cite journal |last1=Stoddart |first1=Andy |last2=Batty |first2=Chris |title=The Elegant Tern in Britain and Europe. |journal=British Birds |date=2019 |volume=112 |issue=2 |pages=99–109}} It has nested in Spain,{{cite journal | last=Dufour | first=Paul | last2=Pons | first2=Jean-Marc | last3=Collinson | first3=J. Martin | last4=Gernigon | first4=Julien | last5=Ignacio Dies | first5=J. | last6=Sourrouille | first6=Patricia | last7=Crochet | first7=Pierre-André | title=Multilocus barcoding confirms the occurrence of Elegant Terns in Western Europe | journal=Journal of Ornithology | volume=158 | issue=2 | date=2017 | issn=2193-7192 | doi=10.1007/s10336-016-1380-0 | doi-access=free | pages=351–361 | url=https://aura.abdn.ac.uk/bitstream/2164/9090/1/JORN_D_16_00029_R2.pdf | access-date=2025-02-08}}José Ignacio Dies, Ana Abad & Miguel Chardí: [https://www.birdguides.com/articles/first-record-of-multiple-elegant-tern-nests-in-spain/ First record of multiple Elegant Tern nests in Spain] at birdguides.com (retrieved 17 August 2008) and has interbred with a Sandwich tern in France. There is also one record from Cape Town, South Africa, in January 2006, the first record for Africa.
Taxonomy and etymology
The current genus name is derived from Greek Thalassa, "sea", and elegans is Latin for "elegant, fine".{{cite book | last= Jobling | first= James A | year= 2010| title= The Helm Dictionary of Scientific Bird Names | url= https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling | publisher= Christopher Helm | location = London | isbn = 978-1-4081-2501-4 | pages =[https://archive.org/details/Helm_Dictionary_of_Scientific_Bird_Names_by_James_A._Jobling/page/n144 144], 383}} Though described in 1822, the genus was largely treated as a synonym of Sterna until a 2005 study demonstrated that the systematics of the terns needed review.{{cite journal |last=Bridge |first=Eli S. |author2=Jones, Andrew W. |author3=Baker, Allan J. |year=2005 |title=A phylogenetic framework for the terns (Sternini) inferred from mtDNA sequences: implications for taxonomy and plumage evolution |url=http://www.cmnh.org/site/Files/Ornithology/MPETerns.pdf |doi=10.1016/j.ympev.2004.12.010 |journal=Molecular Phylogenetics and Evolution |volume=35 |pages=459–469 |pmid=15804415 |issue=2 |access-date=12 September 2016 |archive-date=12 April 2016 |archive-url=https://web.archive.org/web/20160412083752/https://www.cmnh.org/site/files/ornithology/mpeterns.pdf |url-status=dead }}
The closest relative of the elegant tern is Cabot's tern T. acuflavidus, which breeds on the Atlantic coasts of the Americas; this species pair is then next most closely related to the Old World Sandwich tern.{{cite journal |last1=Efe |first1=M.A. |last2=Tavares |first2=E.S. |last3=Baker |first3=A.J. |last4=Bonatto |first4=S.L. |date=2009 |title=Multigene phylogeny and DNA barcoding indicate that the Sandwich Tern complex (Thalasseus sandvicensis, Laridae, Sternini) comprises two species |journal=Molecular Phylogenetics and Evolution |volume=52 |issue=1 |pages=263–267 |doi=10.1016/j.ympev.2009.03.030 |pmid=19348954 |doi-access=free }}{{ cite journal | last1=Collinson | first1=J.M. | last2=Dufour | first2=P. | last3= Hamza | first3=A.A. | last4=Lawrie | first4=Y. | last5=Elliott | first5=M. | last6=Barlow | first6=C. | last7=Crochet | first7=P.-A. | year=2017 | title=When morphology is not reflected by molecular phylogeny: the case of three 'orange-billed terns' Thalasseus maximus, Thalasseus bergii and Thalasseus bengalensis (Charadriiformes: Laridae) | journal=Biological Journal of the Linnean Society | volume=121 | issue=2 | pages=439–445 | doi=10.1093/biolinnean/blw049 | doi-access=free | hdl=2164/10159 | hdl-access=free }}{{cite journal | last=Černý | first=David | last2=Natale | first2=Rossy | title=Comprehensive taxon sampling and vetted fossils help clarify the time tree of shorebirds (Aves, Charadriiformes) | journal=Molecular Phylogenetics and Evolution | volume=177 | date=2022 | doi=10.1016/j.ympev.2022.107620 | doi-access=free | page=107620 | url=https://www.biorxiv.org/content/biorxiv/early/2021/07/16/2021.07.15.452585.full.pdf | access-date=2024-12-22}}
Identification
This is a medium-large tern, with a long, slender, slightly downcurved orange bill, pale gray upperparts and white underparts. It is {{convert|39|-|42|cm|in|abbr=on}} long with an {{convert|76|-|81|cm|in|abbr=on}} wingspan, and a weight of {{convert|190|-|325|g|oz|abbr=on}}.{{Cite web|last=Oiseaux.net|title=Sterne élégante - Thalasseus elegans - Elegant Tern|url=https://www.oiseaux.net/birds/elegant.tern.html|access-date=2020-09-25|website=www.oiseaux.net|language=en}}{{Cite web|title=Elegant Tern Identification, All About Birds, Cornell Lab of Ornithology|url=https://www.allaboutbirds.org/guide/Elegant_Tern/id|access-date=2020-09-25|website=www.allaboutbirds.org|language=en}} Its legs are black. From late summer to winter, the forehead becomes white. Juvenile elegant terns have a scalier pale gray back. The call is a characteristic loud grating noise similar to other Thalasseus terns.
This bird can be confused with the royal tern, but the royal tern is larger and thicker-billed and shows more white on the forehead in winter.{{cite web|url=http://www.sdnhm.org/archive/research/birdatlas/focus/terns.html|title=SDNHM Focus on Royal and Elegant Terns|first=Philip|last=Unitt}} Out of range, it can also be easily confused with the lesser crested tern. See also orange-billed tern, and the external link below.
This species is marginally paler above than the lesser crested tern with a white (not gray) rump, with a slightly longer, more slender bill with a different curve. The black of the crest that comes down from the crown extends through the eye, creating a small black "smudge" in front of the eye even in winter plumage. On royal terns, the black crest stops at the eye, while lesser crested tern has a less shaggy crest.
Ecology and conservation
The total population is around 90,000 pairs, with the majority on islets in the Gulf of California.{{cite web |title=A Drone Crash Caused Thousands of Elegant Terns to Abandon Their Nests |url=https://www.audubon.org/news/a-drone-crash-caused-thousands-elegant-terns-abandon-their-nests |first=Joanna |last=Thompson |publisher=Audubon |date=2021-06-11 |access-date=2021-07-30}} It nests in a ground scrape and lays one or two eggs. Unlike some of the smaller Sterna terns, it is not very aggressive toward potential predators, relying on the sheer density of the nests (often only 20–30 cm apart) and nesting close to other more aggressive species, such as Heermann's gulls, to avoid predation. However, Heermann's gulls do predate some eggs and chicks, though more significant predators are the much larger and more predatory western and yellow-footed gulls.{{cite book | last=Hoyo | first=Josep del | last2=Elliott | first2=Andrew | last3=Sargatal | first3=Jordi | title=Handbook of the Birds of the World: Hoatzin to auks | publisher=Lynx edicions | publication-place=Barcelona | date=1992 | isbn=84-87334-20-2 | language=de | page=}}
In May 2021, 1500 nests with thousands of eggs were abandoned when a drone crash landed near the nesting colony in Bolsa Chica Ecological Reserve, scaring off 2,500 nesting elegant terns and leading to a catastrophic loss.
Elegant Tern Stinson Beach CA 2018-09-20 09-08-37 (45644814722).jpg|Winter plumage, Stinson Beach, California
Elegant Tern Bolsa Chica.jpg|Fishing at Bolsa Chica Ecological Reserve, California
SternaElegansBC.JPG|Bolsa Chica Ecological Reserve, California
References
{{Reflist}}
External links
{{Commons category}}
{{Taxonbar|from=Q524893}}
{{Use dmy dates|date=March 2017}}
Category:Native birds of the West Coast of the United States